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Non-HT Duplicate PPDU FILS Advertisement Frame

Non-HT Duplicate PPDU FILS Advertisement Frame. Authors:. Date: 2012-07-04. Abstract. The very high throughput (VHT) enables transmission bandwidths of 20, 40, 80 and 160 MHz Currently BSS is discoverable only at the primary channel (20 MHz), even if BSS transmits frames at 80 MHz

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Non-HT Duplicate PPDU FILS Advertisement Frame

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  1. Non-HT Duplicate PPDU FILS Advertisement Frame Authors: • Date:2012-07-04 Jarkko Kneckt, Nokia

  2. Abstract • The very high throughput (VHT) enables transmission bandwidths of 20, 40, 80 and 160 MHz • Currently BSS is discoverable only at the primary channel (20 MHz), even if BSS transmits frames at 80 MHz • The BSS should be discoverable at the whole bandwidth in which the BSS operates • The larger scanned bandwidth per operation reduces the number of scanning operations speeds-up the scanning • This ensures initial link setup within 100 ms Jarkko Kneckt, Nokia

  3. Background • The discovery delay may be calculated: • Number of scanning operations * time per scanning operation • It is important to reduce the number of scanning operations as well as shorten the time per scanning operation • The 802.11ai has provided solutions to speed-up discovery in a scanned channel • However, one channel is scanned at a time • The scanning messages may hint the next channel to be scanned Jarkko Kneckt, Nokia

  4. Motivation, channels at 5 GHz Weather radars 5170 MHz 5330 MHz 5490 MHz 5710 MHz 5735 MHz 5835 MHz • 5 GHz has many channels to be scanned • Some mechanism to reduce the number of scanning operations is needed to speed-up the scanning • The turquoise colour shows the channelization of the VHT STA • VHT STA is capable to use 20, 40, 80 and 160 MHz transmission bandwidths as shown 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140 149 153 157 161 165 IEEE channel # 20 MHz 40 MHz 80 MHz only in US Jarkko Kneckt, Nokia

  5. Recap, VHT transmissions summary as defined in 802.11ac • Each STA obtains TXOPs in its primary channel • The channel status (busy /idle) of other channels does not affect to backoff calculation • Larger transmission bandwidth may be used, if CCA of the indicates channel idle a PIFS before the TXOP • The channels are taken into use on specific order • The primary channel may be freely selected • The primary channel defines the secondary20 and secondary40 channels as shown in previous slide Jarkko Kneckt, Nokia

  6. Recap, VHT receptions summary as defined in 802.11ac • Each transmission has a preamble that is transmitted as separate copy for each 20 MHz band • The preamble indicates the PPDU type and transmission bandwidth • The STA obtains a copy of preamble on its primary channel • The VHT PPDU payload is receivable (decoded correctly) only if the receiver has the same primary channel as the transmitter Preamble Payload / Data Preamble Preamble Preamble Jarkko Kneckt, Nokia

  7. Recap, Non-HT Duplicate PPDU as defined in 802.11n/ac • 802.11n defines non-HT duplicate PPDU • The PPDU duplicates the 20 MHz wide MPDUs to larger bandwidth making, each 20 MHz is receiveable as separate frame • 40MHz wide non-HT duplicate PPDU consist of two 20MHz PPDUs • 80 MHz wide non-HT duplicate PPDU consist of four 20MHz PPDUs • The reception of the frame is the same as 20MHz PPDU • The receiver need not to have the same primary channel as the transmitter • 802.11ac uses RTS and CTS frames that are non-HT duplicate PPDUs Preamble Payload Primary channel of the transmitter Payload Preamble Payload Preamble Payload Preamble Jarkko Kneckt, Nokia

  8. Non-HT Duplicate PPDU to enhance passive scanning • FILS Advertisement frame has been discussed to speed-up the passive scanning of the BSS • The FILS Advertisement frame transmitted as non-HT Duplicate PPDU makes the BSS discoverable for its whole transmission bandwidth • Larger bandwidth is the only differentiating feature for FILS Advertisement frame from Measurement Pilot or Probe Response frames Preamble Payload/FILS Advertisement Primary channel of the transmitter Payload/FILS Advertisement Preamble Payload/FILS Advertisement Preamble Payload/FILS Advertisement Preamble Jarkko Kneckt, Nokia

  9. Link Setup after reception of FILS Advertisement • A STA may transmit frames to FILS Advertisement frame transmitter, when it has the same primary channel as FILS Advertisement transmitter • Normal FILS signaling is performed at the same primary channel Jarkko Kneckt, Nokia

  10. Advantages • More channels are scanned in a single scanning operation • The discovery is faster, for instance 80 MHz may be scanned instead of 20 MHz • The amount of scanning operations is reduced • This makes discovery delays acceptable to FILS Requirements, i.e. initial link setup < 100ms • The mechanism is simple, no PHY changes • No new PPDU type is needed • Transmission and reception are already defined in 802.11ac Jarkko Kneckt, Nokia

  11. Motion • Move to add the following text to the clause 6 of TGai Specification Framework document (11-12/0151r08): • ” 802.11ai shall enable scanning frames transmission as non-VHT duplicate PPDUs at 20, 40, 80 and 160 MHz” Jarkko Kneckt, Nokia

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